Mercury vapor detector



Dec. 31, 1940. WQQDSON 2,227,117

MERCURY VAPOR DETECTOR Filed May 1, 1940 F73. I. was

Invent, or: Thomas T Woodson,

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Patented Dec. 31, 1940.

MERCURY VAPOR DETECTOR Thomas'T. Woodson, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Applicationlv lay '1, 1940, Serial No. 332,774

' 5 Claims. (01. 250-415) My invention relates'to apparatus for detecting the presence of minute quantities of mercury vapor the air or in a gasand particularly to apparatus of that. character'which depends for =6 its operation upon the absorption of certain ultra violet radiation by any mercury vapor which may .be present. It is the object of my invention to provide an improved mercury vapor detecting apparatus which is simple in. construction, convenient to operate, has a high degree of sensitivity, and provides adequate security against the escape of mercury vapor, which under certain circumstances may constitute a health hazard or an economic loss.

My invention will be better understood from the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

Referring to the drawing, Figs. 1 and 2 are, respectively, a front elevation and a top view of one embodiment of my invention and Fig. 3 shows a detail thereof drawn to a larger scale. In the drawing, the apparatus comprising my invention is shown mounted within the enclosing casing l which is provided with the handle 2 for convenience in carrying it about. The casing has the front side or cover 3 removably attached thereto as by thumb screws whereby one may readily obtain access to the apparatus. Supported by the cover are the two instruments 4 and 5 by which readings are taken of such quantities as the voltage and the amount of mercury vapor present in the sample being tested. The cover 3 also carries the chassis 6 upon which is mounted most of the components of the associated electrical circuits.

The testing apparatus comprises the absorption chamber 1, which preferably is cylindrical in shape, and which is provided with right-angle, forwardly-extending portions 8 at'the opposite ends thereof. The sample of air or gas to be examined is drawn through the absorption chamber by means of the motor-driven blower 9, the intake side of which connects through the pipe II] with one end of the chamber. The opposite end of the chamber is provided with the intake pipe H which is adapted to be connected by means of a suitable hose with the source of air or gas to be tested. The outlet l2 of the blower 9 may also connect through a hose to the outside air or to a closed system. As indicated by the drawing, the mercury vapor lamp I4 and the photoelectric device [5 are mounted in the chamber at opposite ends thereof, the lamp and the device being supported and sealed in the right-angle portions 8 of the chamber. This arrangement greatly facilitates the insertion and removal of both the lamp and photoelectric device since the two right-angle portions face the front or cover 3 of the enclosing casing.

The means which I have provided for securing the lamp and the photoelectric device in the absorption chamber in a manner by which they may be readily inserted and removed and also securely sealed in position to prevent the escape of vapor laden air or gas, is shown in detail in Fig. 3. Between the part 8 of the chamber and the base l6 of the device l5 are the parallel spaced rings [1 and I8 which are adapted to be drawn together by the clamp screws l9. Between the two rings l1 and H! are the inner and outer concentric rings 20 and 2|, respectively, which rings are composed of resilient material such as rubber. To insure that these rings deform in the desired manner, they are provided with the grooves 22 and 23 on their adjacent faces. When the two rings l1 and I8 are drawn together by the adjusting screws, the inner ring 20 is caused to swell or bulge inwardly, thereby engaging the base 16 and the outer ring 2| is caused to swell or bulge outwardly, thereby engaging the wall of the part 8 of the absorption chamber. By this means, the photoelectric device is centrally and firmly secured in the absorption chamber and, at the same time, the joint between the base and the chamber is sealed against the escape of vapor-laden air or gas. While I have shown and described the securing and sealing means as applied particularly to the photoelectric device, it will be understood that the same means is provided for securing the mercury vapor lamp in the absorption chamber.

By means of the apparatus which I have provided, the mercury lamp and the photoelectric device are readily inserted into and removed from the absorption chamber since the ends of the absorption chamber as well as the clamp screws face the front of the enclosing casing. The arrangement also provides easy access to the electrical terminals and makes unnecessary the provision of high insulation resistance terminal bushings for the device. The clamping means, y which the bases of the lamp and photoelect device are secured in the chamber, also functions to effectively seal the connection.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a mercury vapor detector, an enclosing casing having a removable cover on one side thereof, an elongated absorption chamber mounted in the casing having end portions extending at right angles thereto toward said side, a motordriven blower in said casing connected with said chamber by which vapor-laden air or gas may be drawn therethrough, a mercury vapor lamp and a light sensitive device in said chamber, means for clamping and sealing said lamp and said device each in the end of of one of said end portions, said clamping and sealing means having operating members arranged to be accessible from said side.

2. In a mercury vapor detector, an enclosing casing having a removable cover on one side thereof, an elongated absorption chamber mounted in the casing having'end portions extending at right angles thereto toward said side, means for passing vapor-laden air or gas through the chamber, a mercury vapor lamp and a light sensitive device in said chamber and means for simultaneously securing and sealing them each in the end of one of said end portions.

3. In a mercury vapor detector having a tubular absorption chamber adapted to receive air laden with mercury vapor and containing lightproducing and receiving devices each having a cylindrical base, means for mounting and sealing each of said bases in said chamber comprising spaced rings, inner and outer resilient concentric rings therebetween, and means for clamping together said first-mentioned rings to cause the inner ring to engage a base and the outer ring to engage the wall of said chamber.

4. In a mercury vapor detector having a tubular absorption chamber adapted to receive air or gas laden with mercury vapor and containing light-producing and receiving devices each having a cylindrical base, means for mounting and sealing each of said bases in said chamber comprising a plurality of parallel spaced rings, inner and outer resilient concentric rings therebetween and means for clamping together said first-mentioned rings, said resilient rings having means for causing the inner ring to deform inwardly to engage a base and for causing the outer ring to de-- ,form outwardlyto engage the wall of said chamber in response to the pressure of said first-mentioned rings.

5. In a mercury vapor detector having a tubular absorption chamber adapted to receive air or gas laden with mercury vapor and containing light-producing and receiving devices each having a cylindrical base, means for mounting and sealing each of said bases in said chamber comprising a plurality of parallel spaced rings, inner and outer resilient concentric rings therebetween, and means for clamping together said first-mentioned rings, said inner ring having a groove on its outer surface and said outer ring having a groove on its inner surface.

THOMAS T. WOODSON. 

